Valve control for the head pressure in refrigerating systems



Dec. 9, 1952 KRAMER 2,621,051

VALVE CONTROL FOR THE HEAD PRESSURE IN REFRIGERATING SYSTEMS Filed Nov. 13, 1948 IN VEN TOR.

BY 8 a a S w ATTORNEYS Patented Dec. 9, 1952 VALVE CONTROL FOR THE HEAD PRESSURE IN REFRIGERATING SYSTEMS Israel Kramer, Trenton, N. J assignor to Kramer Trenton Company, Trenton, N. J a corporation of New Jersey Application November 13, 1948, Serial No. 59,836

Claims.

This invention relates to a valve control for the head pressure in refrigerating systems and has for an object to provide a valve'controlled by-pass associated with a modulating valve positioned in the discharge line between the compressor and condenser of refrigerating apparatus for the purpose of maintaining satisfactory functioning in case of failure of the modulating valve to open or to open sufiiciently as called for by head pressure conditions.

Another object is to provide such a device in which a by-pass conduit spans the modulating valve in order to provide an auxiliary passage for gas from the compressor to the condenser in the event the main conduit designed for such passage is wholly or partly closed through failure of the modulating valve properly t function.

Another object is to provide such a device in which the by-pass that spans the modulating valve embodies a valve for regulating the extent to which the by-pass is open, which regulating valve is governed by the pressure in the discharge line between the compressor and the modulating valve, or in which the by-pass itself is of such a form that its functioning is governed by the said pressure.

Another object is to provide such a device in which the modulating valve is governed by the pressure in the discharge line between the compressor and the said by-pass.

A further object is to provide certain improvements in the form, construction and arrangement of the parts whereby the above named objects and others inherent in the invention may be effectively attained.

A practical embodiment of the invention is shown in the accompanying drawing, in which Fig. 1 represents diagrammatically the application of the pre ent invention to refrigerating apparatus such as that disclosed in United States Patent No. 2,440,146 granted in my name on April 20, 1948;

Fig. 2 represents an enlarged detail vertical section, partly in elevation, showing the construction and arrangement of the modulating valve and its associated valve controlled by-pass;

Fig. 3 represents a detail side elevation showing a modified form of by-pass; and

Fig. 4 represents a similar view showing a second modified form of by-pass.

In connection with the installation of refrigerating apparatus it is sometimes desirable in view of building structure or arrangement to locate the compressor unit, including the condenser, out of doors. we gh is feasible when the condenser is of the air-cooled type. However, at geographical points where the temperature is normally low or where winters are severe, efficiency in operation of a refrigerating system thus installed, which employs a volatile refrigerant, is seriously handicapped when the ambient temperature at the condenser is below freezing, particularly with respect to proper supply of refrigerant to the evaporator and proper hot gas defrosting of the evaporator. The diificulty with respect to proper supply of refrigerant to the evaporator results chiefly from evaporation or boiling of the refrigerant in the pipeline leading to the evaporator which could take place as a result of too much loss of pressure in the line or too much increase of temperature surrounding the line at some point between the receiver and the expansion valve or its equivalent. This undesirable condition is likely also to affect the functioning of the expansion valve because of the flow of refrigerant to it at a greatly reduced pressure, and also because of the portion of the refrigerant that is in the form of vapor in the line. This vaporized portion of the refrigerant not only performs no useful function when passed by the expansion valve to the evaporator, but it also materially reduces the supply of liquid refrigerant due mainly to the fact that the vaporized form has a volume more than thirty times that of the liquid form and hence occupies a large part of the refrigerant liquid supply line. The difficulty with respect to hot gas defrosting of the evaporator, above mentioned, is especially unfortunate at times when the water vapor load from substances in the refrigerator is high at the evaporator while the temperature surrounding the condenser and compres or unit is low. This causes ice to form rapidly on the evaporator and there is not sufficient heat in the system to perform the defrost ng step adequately because of the low tem erature at the compre sor unit. This undesirable condition is furthermoreaggravated when the refrigerating system is, for one reason or another, subject to long periods during which the compressor is not in operation.

The difiiculties or disadvantages just ment oned, as well as others which are encountered as a result of low temperature effects upon the condenser and compressor have been very largely eliminated by the invention which forms the subject matter of an application for United States Patent which was filed by Otto J. Nussbaum on June 20, 1947, and was given Serial Number 756,050, now refiled by Otto J. Nussbaum and Frank C. Obert under Serial No. 188,522, and

issued on August 14, 1951, as Patent Number 2,564,310, which invention includes means Whereby gas from the compressor discharge may be caused wholly or partially to by-pass the condenser and travel directly to the receiver, and provides, in one or more forms thereof, a modulating valve positioned in the discharge line between the compressor and condenser for controlling the relative amounts of gas from the compressor which may pass through the condensor to the receiverand through the by-pass from the compressor directly to the receiver. The present invention is directed to improvement in the functioning, of the modulating valve thus arranged in a refrigerating system and to insure against unsatisfactory performance of the refrigerating system or injury thereto arising from faulty operation of the modulating valve.

Turning now to the embodiment of the invention illustrated in the accompanying drawing, a compressor, which may be of any well known or approved form, is denoted by l, and its discharge is connected with a T-coupling 2, from which hot gas pipe 3 leads to and enters at the top of a vessel or container 4, which may be composed of any suitable material, such as steel or iron, and is almost filled with a suitable liquid 5, such, for instance, as a solution of alcohol and water, or Prestone and water, whereby a space 6 remains above the liquid. The pipe 3 takes the form of a coil 1 in the lower part of the vessel 4 and thence extends upwardly through the top of the vessel and leads, through a branch pipe 8, to a receiver 9 of any suitable form, which latter is connected by a pipe 10 with an expansion valve ii, that is in turn, connected by a pipe l2 with an evaporator I3, which may be of any approved or desired construction. The usual fan I4 is mounted adjacent the evaporator for the purpose of circulating the chilled air, and it is provided with wires 15, I5, for connection to a suitable source of current (not shown), such, for instance, as a battery, generator or service supply line. From the evaporator 9, a suction pipe line It leads into the upper part of a tank [1 which is located in the vessel 4 so as to be surrounded by the liquid 5 therein, and extends upwardly into the top of the said vessel. From the upper end of the tank H a continuation of the suction pipe marked l8 runs to the intake port of the compressor l. The tank I! is preferably composed of a suitable metal, such as sheet steel, and it and the vessel 4 are surrounded by an appropriate heat-cold insulating material I 9, preferably confined within an exterior casing 20, that may also be composed of sheet metal such as steel or iron. Any appropriate means (not shown) may be provided for supporting the bottom of the tank t7 within the vessel 4, and a pipe 2!, preferably of very small diameter, connects the lower part of tank I! with suction pipe [8 at a point near the compressor for the purpose of draining off any oil which may accumulate in tank ll. To promote this last named function, the bottom of tank ll is preferably located higher than the intake or suction port of the compressor.

The evaporator, its fan, and the expansion valve are housed within a refrigeration chamber of any appropriate construction, two walls of which are marked 22, 23. A feeler bulb 24 is associated with suction pipe H5 at a point adjacent the evaporator l3, and is connected by a small diameter pipe 25 with the expansion valve H for the purpose of regulating the action of the latter, as is common practice and well understood in this industry. The refrigerant feed pipe l0 and the suction pipe it both pass through a heat exchanger 26, which may be of any well known or approved construction, for the purpose of regulation of the temperature of the refrigerant being fed to the expansion valve and control of the relative temperature of the infiowing liquid refrigerant and outflowing vaporized refrigerant, all of which is again well understood and familiar practice in this field. If desired, a manually operable valve 2'! may be fitted in feed pipe H] for the purpose of controlling the flow of refrigerant from the receiver 9 to the expansion valve H.

The apparatusinoludes hot gas evaporator defrosting means which comprises a pipe 28 which runs from T-coupling 2 that is connected with the compressor discharge line to the evaporator l3, and in said pipe 28 is positioned a solenoid valve 29, which has its terminals connected by wires 30, 3|, with means for periodically opening the valve, such, for instance, as any well known or approved form of electric timer, here indicated by 32, a number of which are available in the open market so as not to require either illustration or description herein other than to say that the timer may be set by the installing engineer to become active at certain times, say, every three hours, and to continue in action for predetermined periods, such, for instance, as six minutes. It will be understood that periodic opening of solenoid valve 29 will permit hot gas from the compressor to flow through pipe 28 to the evaporator for the purpose of accomplishing defrosting of the latter. A hand valve 33 may be fitted in pipe 28 intermediate the compressor and solenoid valve 29 for the purpose of closing the pipe if that be desired at any time. The evaporator l3 may be provided with a suitable drain pipe 34 for leading the water resulting from defrosting to the sewer or other disposal point.

The characteristic features of the present invention reside in the connection between the discharge of the compressor I and the usual con denser 35, which latter may be of any well known or approved form and is connected to the receiver 9 by a pipe 36, which may, if desired, be equipped with a hand valve 31.

Compressor discharge line 3 runs, as usual, to the condenser 35 and in the said line there is interposed a modulating valve which is denoted generally by 38 and has its inlet and outlet connected to short pipe sections 39, 40, that are fitted into discharge line 3 by unions 4|, 42. The said modulating valve may be of any well known or approved form and, as such valves are obtainable on the market and are commonly used to control the flow of fluid through conduits, there seems to be no occasion to describe in any detail the construction of the valve other than to say that it includes a valve head 43, which, when depressed, permits fluid to pass from pipe section 39 through the valve into pipe section 49; when elevated and resting on its seat 44, prevents such passage of the fluid; and when in an intermediate position more or less restricts the passage of the fiuid. Actuation of the valve head 43 is controlled by the usual power bellows 45 that works in opposition to the usual spring 43, and the performance of the bellows is governed by the pressure exerted through an actuating tube 61 which opens communication between the top of the modulating valve that houses the bellows 45 and pipe section 39 of the compressor discharge line 3, When the pressure in actuating tube 41 rises to a sufficient degree, bellows 45 will be depressed and valve head 43 will move away from its seat, thus permitting the flow of fluid through the valve from pipe section 33 to pipe section 40. It will be understood that the greater the pressure in tube 4?, the wider the valve will open, so that it may assume any condition from completely closed to completely open. The modulating valve is also provided with the usual adjusting nut 43 that can vary the pressure of spring 36 and, hence the resistance of the latter to compression of bellows 45.

A fluid by-pass conduit is provided in the discharge line 3 to span the modulating valve 38, which by-pass consists of a tube 49 that uprises from pipe section 39; a tube 53 that uprises from pipe section 43, and a relief valve 5| that is coupled to tubes 49 and 53 as indicated at 52 and 53. The relief valve has a head 54 which is urged toward its seat 55 by an expansion spring 53, the tension of which may be varied by an adjusting nut 57 which is threaded to the top of the valve. It will be clear from the immediately foregoing description that when, for any reason, the modulating valve 38 fails to open or to open widely enough to accommodate the pressure in the discharge line between it and the compressor, the relief valve 5! may open and permit passage of the fluid through by-pass tubes ii) and 50 and thence on to the condenser 35, thus relieving excess pressure in the compressor discharge line which might cause injury to the apparatus such, for instance, as overload of the compressor motor, while continuing the functioning of the system in supplying refrigerant through the condenser and receiver to the expansion valve. If desired, a manually operable valve 58 may be positioned in the line 3 between the modulating valve and the condenser for controlling the amount of refrigerant permitted to pass therethrough; and another hand valve 59 may be fitted in branch pipe 8 for controlling the flow of the fluid therethrough.

In operation, the hot gas from the compressor discharge passes through the coil 1 and heats the liquid 5 in the vessel 4, and the liquid, in turn, heats the tank 11. The hot gas passing through coil 7 continues through pipe 3 to the condenser 35 and/or receiver 9, according to the condition of the modulating valve 38, as will be hereinafter more fully described. When the electric timer 32 is actuated to perform a defrosting of the evaporator l3, solenoid valve 29 is opened and the hot gas from the compressor flows through pipe 28 directly to the evaporator to melt the ice thereon. In performing this function, the chill from the ice condenses the hot gas so that it leaves the evaporator in the form of a liquid which passes through pipe 13 and enters tank ll, whereupon the heat of the latter vaporizes the liquid so that it may be drawn as a gas through pipe It to the intake or suction side of the compressor. At the end of the defrosting period electric timer 32 closes valve 29 and the normal operation of supplying refrigerant to the evaporator is resumed.

Referring particularly to the functioning of the characteristic features of the present invention, the installing engineer or operator in charge adjusts nut 43 of the modulating valve 38 with appropriate regard for local temperature conditions, e. g., to open under a head pressure of 110 pounds per square inch when the ambient temperature is degree Fahrenheit. After such setting or adjustment, the functioning of the modulating valve becomes automatic since an increase in pressurein the discharge line 3 due, for instance, to a rise in ambient temperature will be effective through actuating tube 41 to increase the opening of the modulating valve and thereby reduce the head pressure in the discharge line; while lowering of the pressure in the said line due, for instance, to a drop in ambient temperature will tend to close the modulating valve under the influence of spring 46, with a following increase in head pressure.

The relief valve 5! in the by-pass line 49, 50, should be set so as to permit this valve to open when the pressure in the compressor discharge line 3 adjacent the modulating valve exceeds the opening pressure at which the latter has been set as hereinabove mentioned. Therefore, should the modulating valve fail to open under such conditions, the relief valve will open and permit fluid in the line 3 to by-pass the modulating valve through tubes 49 and 50, thus continuing the functioning of the apparatus as though the modulating valve had opened and also avoiding injury to the system due, especially, to an undesirable back pressure upon the compressor and an overload upon its motor.

The branch pipe 8 which leads from discharge line 3 directly to receiver 9 is of value particularly when the ambient temperatur falls so low as to cause a sharp reduction of the pressure in the discharge line, under which conditions the modulating valve will close and the hot gas from the compressor will flow directly to the receiver, without passing through the condenser, in which case the receiver in effect serves as a condenser and supplies liquid refrigerant to the expansion valve under a pressure greater than would be the case if the gas were required, under the stated conditions, to pass through the condenser before reaching the receiver.

It will thus be seen that the modulating valve automatically and almost instantly controls the head pressure in the discharge line; that it also controls the relative proportions of refrigerant which pass through the condenser and directly to the receiver; and that the by-pass which spans the modulating valve and is. equipped with a relief valve, insures against interruption in operation, inefficient operation, and/or injury to the apparatus in case of whole or partial functioning failure of the modulating valve.

While the subject matter of this invention is shown and described in a system which includes hot gas defrosting of the evaporator and also includes means for leading gas from the compressor discharge directly to the receiver without passing through the condenser; it should be noted that this invention is useful and effective in other arrangements which do not include both or either of the features just named. In other words, the modulating valve and its relief valve controlled by-pass are of sensible value and notable importance in refrigerating systems where they do nothing more than control the head pressure in the discharge line from the compressor to the condenser, regardless of any salutary effect with respect to maintenance of hot gas supply for adequate defrosting and maintenance of proper supply to the expansion valve of liquid refrigerant at desirably high pressure.

The modulating valve and its accompanying by-pass with relief valve constitute a simple and comparatively inexpensive device which may be manufactured and marketed as a unit for installation not only in newly produced refrigeration systems but also in existing systems, as it is only necessary to sever the compressor discharge line at a point between the compressor and condenser, and couple in the unit by the use of pipe connections 4|, 42, or equivalent elements.

The modified form of the invention shown in Fig. 3 differs from the form of Figs. 1 and 2 in that a capillary tube 60 is substituted for the tube 49, and the relief valve 5| is omitted. The internal size of the tube 80 is predetermined so that it will function when the pressure affecting it reaches a certain degree, as is well understood by those skilled in this industry, and it serves the same purpose as the relief valve.

In the second modified form of the invention shown in Fig. 4, a plug 6| having a calibrated orifice 62 is substituted for the relief valve 5| and performs the same function; the orifice being calibrated so as to respond to a predetermined pressure. The plug may be secured in position by any suitable means, such as sweating, swaging, or set screw.

It should be pointed out that, in connection with all the forms of the invention, the portions of the conduits 39 and 40 adjacent the modulating valv 38 could be integral extensions of the valve terminals instead of separate pipes fastened to the valve, and that the parts 41, 49,50 and 60 could be connected with such integral extensions. This, of course, would merely amount to increasing the size of the modulating valve casting in accordance with the choice of the manufacturer, and I intend that the claims be construed in the light of this explanation so as to cover such a structure in which the said parts 47, 49, 50 and 60 are connected to integral extensions of the valve 38.

It will be understood that various changes may be resorted to in the form, construction, arrangement and material of the several parts without departing from the spirit or scope of the invention; and hence I do not intend to be limited to details herein shown or described, ex-

cept as they may be included in the claims or be required by disclosures of the prior art.

What I claim is: 1. Control mechanism adapted for installation in the compressor discharge line of refrigerating apparatus comprising, an automatic modulating valve having a fluid passage therethrough provided with inlet and outlet terminals, fluid conduits connected with the terminals of said passage, a by-pass fluid conduit spanning said valve and connected with said first named conduits, and

a valve actuating tube connecting the modulating valve with the conduit that is connected to the inlet terminal of said passage.

2. Control mechanism adapted for installation in the compressor discharge line of refrigerating apparatus comprising, an automatic modulating valve having a fluid passage therethrough provided with inlet and outlet terminals, fluid conduits connected with the terminals of said passage, a by-pass fluid conduit spanning said valve and connected with said first named conduits, a relief valve in said by-pass, and a valve actuating tube connecting the modulating valve with the conduit that is connected to the inlet terminal of said passage.

'3. Control mechanism adapted for installation in the compressor discharge line of refrigerating apparatus comprising, an automatic modulating valve having a fluid passage therethrough provided with inlet and outlet terminals, fluid conduits connected with the terminals of said passage, a by-pass fluid conduit spanning said valve and connected with said first named conduits, a relief valve in said by-pass, and a valve actuating tube connecting the modulating valve with the conduit that is connected to the inlet terminal of said passage at a point spaced further from the modulating valve than the point at which the by-pass conduit is connected to said inlet terminal conduit.

4. Control mechanism adapted for installation in the compressor discharge line of refrigerating apparatus comprising, an automatic modulating valve having a fluid passage therethrough provided with inlet and outlet terminals, fluid conduits connected with the terminals of said passage, a capillary by-pass fluid conduit spanning said valve and connected with said first named conduits, and a valve actuating tube connecting the modulating valve with the conduit that is connected to the inlet terminal of said passage.

5. Control mechanism adapted for installation in the compressor discharge line of refrigerating apparatus comprising, an automatic modulating valve having a fluid passage therethrough provided with inlet and outlet terminals, fluid conduits connected with the terminals of said passage, a by-pass fluid conduit having a, calibrated orifice spanning said valve and connected with said first named conduits, and a valve actuating tube connecting the modulating valve with the conduit that is connected to the inlet terminal of said passage.

ISRAEL KRAMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Country Date 552,793 Stoner Jan. 7, 1896 929,852 Hosford Aug. 3, 1909 1,190,681 Spitzer July 11, 1916 1,394,615 Erwin Oct. 25, 1921 1,425,338 Ray Aug. 8, 1922 1,791,012 Ray Feb. 3, 1931 1,850,963 Sponar Mar. 22, 1932 2,222,141 Denison Nov. 19, 1940 2,299,847 Price Oct. 27, 1942 2,336,473 Eilers Dec. 14, 1943 2,564,310 Nussbaum Aug. 14, 1951 

